Assembly-Induced Emission Enhancement in Glutathione-Capped Bimetallic Gold and Copper Nanoclusters by Al(3+) Ions and Further Application in Myricetin Determination

A significant emission enhancement (>100-fold) of glutathione-capped bimetallic gold and copper nanoclusters (AuCuNC@GSH) was achieved by assembling with Al(3+) ions and by assembly-induced emission enhancement (AIEE). Further chelation of myricetin to Al(3+) resulted in emission quenching of AuCuNC-Al(3+), which was applied to specifically detect myricetin. Two linear responses were shown in the range of 0–1.5 μM and 1.5–50 μM, separately, leading to a low limit of detection at 8.7 nM. The method was successfully and accurately applied to myricetin determination in grape juice, which showed good application for real samples. Finally, the in-depth mechanism revealed that both the chelation of myricetin and Al(3+) and the inner filter effect (IFE) between myricetin-Al(3+) and AuCuNC-Al(3+) greatly contributed to the quenching response of myricetin. Therefore, the present study provides an easy way to improve the fluorescence property of metal nanoclusters. Additionally, it supplies a cost-effective and easily performed approach to detect myricetin with high selectivity and sensitivity.